The present invention generally relates to a fuel supply system for a vehicle and more particularly to a system supplying fuel to an internal combustion engine or fuel cell of an automotive vehicle.
Ever since the advent of automotive vehicles, those who design and manufacture automotive vehicles have had the goal of producing a propulsion system that minimizes use of fossil fuels and does not generate byproducts that are harmful to humans or the environment. The majority of conventional automotive vehicles include an internal combustion engine that is fueled by gasoline or diesel fuel. These automotive vehicles generally can travel relatively significant distances between refueling and can obtain up to about 50 miles per gallon of gasoline. Typically, however, such fuel economy can only be achieved at the expense of power and size of the vehicle. Also, conventional internal combustion engines contribute significant amounts of pollution to the environment, particularly in large cities where there are many vehicles on the road. Further, the exhaust from these engines includes dangerous levels of carbon monoxide.
One approach to solve some of the above problems is to feed the supply of fuel through a vaporization device so as to vaporize the fuel prior to introducing it to the internal combustion engine. By first vaporizing the fuel, greater fuel economy can be obtained while reducing harmful exhaust emissions. Examples of such vaporization devices are disclosed in commonly assigned U.S. Pat. Nos. 5,123,398 and 5,666,929. It was believed that the fuel bums more efficiently and completely when introduced to the engine as vapor. One problem experienced with the use of such vaporization devices is that the spark plugs, engine cylinders, and valves would quickly become blackened with soot, which was believed to be carbon.
An alternative approach to solving the above environmental problems with internal combustion engines is to power the vehicles with an electric motor. Electricity to drive the motor is supplied from a number of batteries in a true electric vehicle. A problem with such electric vehicles is that they do not have the range of a vehicle powered by an internal combustion engine. Also, the batteries may take a relatively long time to recharge. Because people have grown accustomed to the greater range and refueling convenience of vehicles powered with internal combustion engines, electric vehicles have not been widely accepted by the public.
To increase the range of a vehicle powered with an electric motor, a hybrid electric vehicle has been developed. In a hybrid electric vehicle, a small internal combustion engine is provided to run an alternator that recharges the batteries as the vehicle is being driven. In some forms of hybrid electric vehicles, both the batteries and the alternator driven by the small internal combustion engine, power the electric motor. Because the internal combustion engine in a hybrid vehicle need only drive the alternator at a constant speed, the engine may be much smaller and lighter than a conventional internal combustion engine. While hybrid electric vehicles show much promise, they nevertheless still utilize an engine that pollutes the atmosphere and generates dangerous levels of carbon monoxide.
Another type of system for powering a vehicle utilizes a fuel cell. Fuel cells consume a constant supply of fuel to generate electricity for driving an electric motor. Typical fuel cells include an anode and a cathode and operate by feeding a supply of hydrogen through a separator membrane between the anode and the cathode so as to generate electricity through a redox reaction. Fuel cells are drawing a great deal of interest because of their fuel economy and their lack of polluting byproducts. Fuel supply systems for such fuel cells are known that generate the supply of hydrogen from supplies of gasoline and water. However, because fuel supply systems can take up to ten minutes to warm up and generate sufficient quantities of hydrogen to fuel the fuel cell and hence drive the electric motor, large and expensive batteries must be provided in the vehicle to generate sufficient electricity for initial travel following start-up. Currently, fuel cells are too expensive for production due to the need for the expensive batteries required for start-up.
Another fuel supply system proposed for vehicles is to power internal combustion engines with alternative fuels, such as alcohol, ethanol, methane, and hydrogen, so as to reduce the presence of environmentally harmful exhaust gasses. The use of alternative fuels has not become commercialized, however, due to their requirements that the current infrastructure would require change. For example, gas stations would have to all change and begin offering these alternative fuels in addition to gasoline since vehicles consuming gasoline would still be in existence. Also, alternative fuels such as methane and hydrogen are combustible gasses that would have to be stored in a pressurized container within the vehicle and, therefore, would pose a severe danger to the vehicle occupants.
It has been proposed that internal combustion engines may be run on hydrogen that is produced by converting hydrocarbon fuel into hydrogen. See, for example, U.S. Pat. Nos. 3,682,142; 4,476,817; 4,008,692; 4,003,343; 3,920,416; 5,379,728; 5,085,176; 5,207,185; 5,092,303; and 5,156,114. In some of these systems, heat from the engine exhaust is used to convert the hydrocarbons to hydrogen. Clearly, such systems cannot immediately generate hydrogen when the engine is cold or on ignition start-up. Some of these systems rely upon an expensive catalyst, such as platinum, to convert hydrocarbons to hydrogen. At least one of these systems burns hydrogen supplied from a pressurized storage tank to supply heat for the conversion. Again, the use of such pressurized hydrogen storage tanks is not desirable due to the hazard it presents. Additionally, some of these disclosed systems mix steam with the fuel to generate hydrogen and reduce pollutants. However, the heat required to produce steam from stored water, which may be cold, is not immediately available on cold engine start-up.
Accordingly, an aspect of the present invention is to provide a fuel supply system that does not require changes in the current fuel distribution infrastructure and yet obtains significantly better fuel economy than vehicles currently available. It is another aspect of the present invention to provide a fuel supply system that exhausts significantly less carbon monoxide and NOX than conventional internal combustion engines. An additional aspect of the present invention is to provide a fuel supply system that may be used to supply fuel to current internal combustion engines. Yet another aspect of the present invention is to provide a fuel supply system that uses widely available forms of gasoline or diesel fuel. The fuel supply system of the present invention may also use other forms of fuel such as methane, ethane, or alcohol.
It is another aspect of the invention to provide a system for supplying hydrogen to an internal combustion engine without requiring pressurized storage of hydrogen. Yet another aspect of the invention is to provide a hydrogen fuel delivery system which allows immediate start-up of a cold engine and which does not rely upon heat of the engine to convert hydrocarbon fuel into hydrogen.
To achieve these and other aspects and advantages, the fuel supply system of the present invention as used for an internal combustion engine comprises a water supply for supplying water, an air inlet, a fuel supply for supplying fuel, and a conversion device coupled to the water and fuel supplies and the air inlet for generating hydrogen from the water and fuel, and supplying the hydrogen to an intake manifold of the internal combustion engine. The conversion device includes heating means for simultaneously heating the water and fuel to a temperature at which the water and fuel convert to hydrogen. Successful experimental tests conducted on a prototype engine system confirm these objectives.
Another aspect of the present invention is to provide a fuel supply device for a fuel cell that can supply hydrogen to the fuel cell immediately upon vehicle start-up to thereby eliminate the need for expensive batteries to provide electricity to the electric motor while the fuel supply system warms up. Still another aspect of the present invention is to provide a fuel supply device for a fuel cell that generates hydrogen from gasoline and water. To achieve these and other aspects and advantages, the fuel supply apparatus of the present invention as used for supplying fuel to a vehicle propulsion system comprises a vaporization chamber, an inlet nozzle for introducing fine droplets of fuel and water into the vaporization chamber, an air inlet for introducing air into the vaporization chamber to create turbulence in the chamber, an electrical heater in the vaporization chamber for heating the turbulent fuel/water mix at a temperature that causes the mix to convert into hydrogen and harmless byproducts, and an outlet for supplying the generated hydrogen to the vehicle propulsion system.
These and other features, advantages, and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims, and appended drawings.